Ch 9 Muscles Flashcards
1
Q
What are the three types of muscular tissue
A
cardiac, skeletal, smooth
2
Q
muscle tissue is _______ the body’s mass
A
half
3
Q
elongated cells
A
muscle fibers
4
Q
organ attached to bone and skin muscle fibers striated voluntary contract rapidly requires nervous system stimulation
A
skeletal muscle
5
Q
only in the heart
striated
involuntary
does not require nervous system stimulation
A
cardiac muscle
6
Q
in walls of hollow organs
not striated
involuntary
can contract without nervous system stimulation
A
smooth muscle
7
Q
ability to receive and respond to stimuli
A
excitability
8
Q
ability to shorten forcibly when stimulated
A
contractility
9
Q
ability to be stretched
A
extensibility
10
Q
ability to recoil to resting length
A
elasticity
11
Q
four muscle functions
A
Movement of bones or fluids (e.g., blood)
Maintaining posture and body position (counteracting gravity)
Stabilizing joints
Heat generation
12
Q
served by one artery, one nerve, and one or more veins
A
skeletal muscle
13
Q
dense irregular connective tissue surrounding entire muscle; may blend with fascia (superficial facia)
A
epimysium
14
Q
fibrous connective tissue surrounding fascicles
A
perimysium
15
Q
groups of muscle fibers
A
fascicles
16
Q
fine areolar connective tissue surrounding each muscle fiber
A
endomysium
17
Q
external to internal external sheath of skeletal muscle
A
epimysium, perimysium, endomysium
18
Q
epimysium fused to periosteum of bone or perichondrium of cartilage
A
direct
19
Q
connective tissue wrappings extend beyond muscle as ropelike tendon or sheetlike aponeurosis
A
indirect
20
Q
plasma membrane
A
sarcolemma
21
Q
cytoplasm
A
cytoplasm
22
Q
splinters
densely packed, rod like elements
contain sarcomeres
exhibit striations
A
myofibrils
23
Q
contractile units contain myofilaments(stripes)
A
sarcomere
24
Q
lighter region in midsection of dark A band where filaments do not overlap
A
H zone
25
line of protein myomesin bisects H zone
M line
26
coin-shaped sheet of proteins on midline of light I band that anchors thin filaments and connects myofibrils to one another
z disc
27
run entire length of an A band
thick filaments
28
run length of I band and partway into A band-actin
thin filaments
29
region between two successive Z discs
sarcomere
30
thin filaments
Extend across I band and partway in A band
Anchored to Z discs
"bean with hat"
Actin myofilaments
31
thick filaments
Extend length of A band
Connected at M line
"head and tail"
Myosin myofilaments
32
regulatory proteins bound to actin
| "hat"
Tropomyosin
33
connects myosin to the z disc
titan
34
connects the actin to m line
Dystrophin
35
surrounds each myofibril
hold on to cistern
function:*regulates calcium levels inside muscle
sarcoplasmic reticulum
36
function: every myofibril contracts at the same time
continuations of sarcolemma
communication(increases surface area)
t tubules
37
Occurs when myosin heads bind to actin
cross bridges
38
During contraction, thin filaments slide past thick filaments actin and myosin overlap more
Occurs when myosin heads bind to actin
sliding filament model of contraction
39
what must happen for a skeletal muscle to contract
activation and excitation
40
Must be nervous system stimulation
| Must generate action potential in sarcolemma
activation
41
contraction coupling
Action potential propagated along sarcolemma
Raise in Intracellular Ca2+ levels must rise briefly
excitation
42
Skeletal muscles stimulated by this
somatic motor neurons
43
Each axon ending forms ______ _______ with single muscle fiber
neuromuscular junction
44
Axon terminal and muscle fiber separated by gel-filled space
synaptic cleft
45
Synaptic vesicles of axon terminal contain neurotransmitter
acetylcholine
46
Junctional folds of sarcolemma contain _____ _____-
ACh receptors
47
events at the neuromusclular junction
Nerve impulse arrives at axon terminal ACh released into synaptic cleft
ACh diffuses across cleft and binds with receptors on sarcolemma
Electrical events generation of action potential
48
steps in the generation of action potential
End plate potential
Depolarization
Repolarization
49
action potential is caused by changes in what
electrical charges
50
local depolarization
end plate potential
51
generation and propagation of an action potential (AP)
depolarization
52
restoring electrical conditions of RMP
repolarization
53
increase of intracellular calcium
EC coupling
54
Time when E-C coupling events occur
| Time between AP initiation and beginning of contraction
latent period
55
force exerted on load or object to be moved
muscle tension
56
no shortening; muscle tension increases but does not exceed load
isometric contraction
57
muscle shortens because muscle tension exceeds load
isotonic contraction
58
three phases of muscle twitch
latent period, period of contraction, period of relaxation
59
events of excitation-contraction coupling; no muscle tension
latent period
60
cross bridge formation; tension increases
period of contraction
61
Ca2+ reentry into SR; tension declines to zero
period of relaxation
62
does muscle contract or relax faster?
contracts
63
what are responses graded by
Changing frequency of stimulation
| Changing strength of stimulation
64
Varying strength of contraction for different demands
| Required for proper control of skeletal movement
graded muscle responses
65
Increased stimulus frequency (muscle does not completely relax between stimuli) second contraction of greater force
wave summation
66
Further increase in stimulus frequency
unfused tetanus
67
If stimuli are given quickly enough, muscle reaches maximal tension
fused tetany
68
No muscle relaxation
muscle fatigue
69
(multiple motor unit summation) controls force of contraction
recruitment
70
no observable contractions
subthreshold stimuli
71
stimulus strength causing first observable muscle contraction
threshold stimulus
72
strongest stimulus that increases contractile force
maximal stimulus
73
Recruitment works on what
size principle
74
muscle shortens and does work
concentric contractions
75
muscle generates force as it lengthens
eccentric contractions
76
Muscle changes in length and moves load
Thin filaments slide
two types
isotonic contractions
77
two types of isotonic contractions
eccentric and concentric
78
Load greater than tension muscle can develop
| Tension increases to muscle's capacity, but muscle neither shortens nor lengthens
isometric contractions
79
Constant, slightly contracted state of all muscles
Due to spinal reflexes
Keeps muscles firm, healthy, and ready to respond
muscle tone
80
available stores of ATP are depleted how quickly
4-6 seconds
81
what is only source used directly for contractile activities
ATP
82
what is ATP regenerated by
Direct phosphorylation of ADP by creatine phosphate (CP)
Anaerobic pathway (glycolysis lactic acid)
Aerobic respiration
83
Glycolysis – does not require oxygen
At 70% of maximum contractile activity:
Bulging muscles compress blood vessels; oxygen delivery impaired
Pyruvic acid converted to lactic acid
anaerobic respiration
84
during anaerobic respiration what diffuses into the blood stream
lactic acid
85
Produces 95% of ATP during rest and light to moderate exercise; slow
aerobic respiration
86
how is fiber type classified
Speed of contraction and Metabolic pathways for ATP synthesis
87
use aerobic pathways
oxidative fibers
88
use anaerobic glycolysis
glycolytic fibers
89
three types of muscle fibers
Slow oxidative fibers; Fast oxidative fibers; Fast glycolytic fibers
90
aerobic exercise leads to what
Results in greater endurance, strength, and resistance to fatigue
May convert fast glycolytic fibers into fast oxidative fibers
91
Resistance exercise (typically anaerobic) results in
muscle hypertophy
Increased mitochondria, myofilaments, glycogen stores, and connective tissue
Increased muscle strength and size
92
Forcing muscle to work hard promotes increased muscle strength and endurance
Muscles adapt to increased demands
Muscles must be overloaded to produce further gains
Overuse injuries may result from lack of rest
overload principle
93
Without neural stimulation muscles atrophy to _____ initial size
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